Method for the packing under aseptic conditions of sterile goods into containers

ABSTRACT

A method for packing sterile goods into containers under aseptic conditions wherein a thermoformable web is introduced into one end of a processing tunnel within which sterile conditions are maintained. As the web passes through the tunnel it is drawn into a series of end-to-end connected open-top containers which are then filled from above with the sterile goods to be packaged. After filling, and while still within the tunnel, a closure in the form of a second web is applied to the upper ends of the containers and heat sealed into place. After the end-to-end connected formed, filled and sealed containers pass out of the opposite end of the tunnel they are then separated from one another by severing.

United States Patent Rausing Oct. 14, 1975 [54] METHOD FOR TI'IE PACKINGUNDER 3,692,468 9/1972 Loliger et a1. 53/167 X ASEPTIC CONDITIONS OFSTERILE 3,766,709 10/1973 Zmsner 53/167 3,783,581 1/1974 Pierce 53/167 XGOODS INTO CONTAINERS 3,820,300 6/1974 Reinecke et a1. 53 110 x [30]Foreign Application Priority Data Aug, 11, 1972 Sweden 10418/72 [52] US.Cl. 53/21 FC; 53/110; 53/167 [51] Int. Cl. B65B 31/02; 13658 55/18 [58]Field of Search 53/167, 184, 21 FC, 110

[56] References Cited UNITED STATES PATENTS 3,267,639 8/1966 Ollier eta1. 53/184 X 3,383,831 5/1968 Goldsmith et al. 53/167 3,478,489 1 H1969Meisner 53/167 3,481,100 12/1969 Bergstrom... 53/184 X 3,583,129 6/1971Rorer 53/112 A 3,583,132 6/1971 Doyen 53/167 X Inventor:

Filed:

Primary ExaminerTravis S. McGehee Attorney, Agent, or FirmPierce,Schefller & Parker A method for packing sterile goods into containersunder aseptic conditions wherein a thermoformable web is introduced intoone end of a processing tunnel within which sterile conditions aremaintained. As the web passes through the tunnel it is drawn into aseries of end-to-end connected open-top containers which are then filledfrom above with the sterile goods to be packaged. After filling, andwhile still within the tunnel, a closure in the form of a second web isapplied to the upper ends of the containers and heat sealed into place.After the end-to-end connected formed, filled and sealed containers passout of the opposite end of the tunnel they are then separated from oneanother by severing.

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METHOD FOR THE PACKING UNDER ASEPTIC CONDITIONS OF STERILE GOODS INTOCONTAINERS The present invention relates to a method for the packingunder aseptic conditions of sterile goods into cntainers, athermoformable material web, after it has been subjected to asterilizing medium or with simultaneous sterilization, being heated upto a temperature required for a thermoforming processing, whereupon theweb or a selected part of the same is subjected to a thermoformingprocessing with the object of forming containers from the web, whichwhilst continuing to be joined to the web and being oriented so that thecontainer openings are situated mainly in the plane of the web, arefilled with the sterile goods intended for packing and are closed inthat the openings of the container are covered by another web, which issealed or in some other manner joined to the first material web at leastalong zones closed in themselves around the container openings with theobject of enclosing the sterile goods in the containers.

In packing technology and especially in packing procedures for suchgoods which normally have limited keeping properties, attention isdirected more. and more towards an improvement of already existingpacking systems or to bringing out new ones which would allow aprolonged keeping quality for the goods packed. By the application ofsuch packing systems it is intended first and foremost that the goodsshould be able to permit a normal distribution, storage and keepinguntil the time of consumption. Demands can be made therefore not only onthe form and special treatment of the goods themselves with regard totheir keeping quality, but also on the manner of packaging them,likewise on the packing container and its material composition. Dairyproducts for example constitute such goods which are referred to hereand packing systems also exist suitable for the aseptic packing of theseproducts in consumer packages.

In one of the known rational methods for the packing of sterile goodsunder aseptic conditions so as to make possible a prolonged keepingquality of the goods, a compound material web is used which comprises afibrous base layer and plastic layer and metal foil layer placedthereon. The web is converted to a tube which is filled with the sterilegoods and which is divided under aseptic conditions to wholly filled andclosed packing units. In another system prefabricated, closed andsterile containers are punctured with a cannula, through which thesterile goods are fed to the interior of these containers. This systemof packing is of course not rational for the packing of such consumptiongoods as foodstuffs. In another packing system a web of plastic materialis used, from which containers are formed by means of vacuum drawing, atleast the filling and closing operations being carried out in an asepticatmosphere.

By the very fact that new plastic materials or combinations of plasticmaterial appear, which present an improved resistance againstpenetration of gas and water vapour, possibilities exist now for themanufacturing of sterile packages consisting of plastic material only.In this connection modifications or improvements of already existingpacking methods have been suggesed, where a plastic material is used forthe forming of the packing container. In these methods container bodiesare often formed by vacuum drawing from a plastic material web heated inadvance, whereupon the containers are filled with the goods intended forpackaging in that for example wafers are applied to cover the openingsof the filled containers, which wafers are sealed to the opening rim ofthe container or to the area close by it. So as to obtain a sterileenvironment when packing a sterile material certain parts of the device,such as the filling and closing elements, have been built into or havebeen enclosed in a chamber, wherein a largely sterile atmosphere ismaintained.

In such packing machines, however, certain problems exist with regard tothe maintenance of sterility in the socalled sterile chamber, which aredue to the fact that already existing machines and systems have not beenfully adapted to the new circumstances. Furthermore, the form and sizeof the sterile chamber necessary for these types of machines have beenunnecessarily complicated and voluminous.

By means of the present invention, however, a method is suggested whichis adapted to a rational packing procedure for a sterile material filledand where aseptic conditions can satisfactorily be maintained at thesame time as such problems and inconveniences which were mentioned abovecan be overcome. The invention is characterized in that a firstthermoformable material web is introduced into a tunnel and is passedthrough the same in such a manner that the material web, together withthe walls of the tunnel, forms a chamber, in which a sterile atmosphereis maintained, the filling of the containers formed and the sealing ofthe filled containers are carried out with the help of a second materialweb in the said chamber, whereupon the filled and sealed containers aremoved out of the tunnel while the combined first and second webs presenta plane upper side, and that the containers are finally separated fromone another by means of a cut through the said two webs.

In the following the invention will be described with reference to theenclosed schematic drawing, wherein FIG. 1 shows in side view and partlyin section a setup for the execution of the method in accordance withthe invention and FIG. 2a-FIG. 2e show in cross-section variousexecutions of the sterile tunnel which forms part of the set-upaccording to FIG. 1.

In FIG. 1 reference indication 1 indicates a tunnel and 2 athermoformable material web which is intended to be introduced into theone end of the tunnel and to be moved out from its other end togetherwith a second material web 3, which is applied to the firstthermoformable material web in the tunnel. The walls of the tunnel 1form, together with the web 2 and the joined first and second webs 2 and3, a sterile chamber 4. The sterile chamber can be provided at its frontend with a pre-treatment chamber 5, which may consist of an extendedpart of the tunnel 1, this chamber being formed similar to the sterilechamber 4, that it to say that the walls of the tunnel together with theweb 2 form the chamber. A pre-treatment chamber 6 is arranged for theintroduction of the said material web 3. This chamber is realizedpreferably as a superstructure on the sterile tunnel l and communicateswith the same via an opening 36 in the tunnel wall.

Underneath the sterile chamber 4 a forming tool 19 is arranged for theforming of container bodies 21 by means of thermoforming processing ofthe material web 2. The forming tool may consist of a forming box whichcomprises at least one, but preferably several forming cavities andwhich is adapted for example for vacuum drawing of the material web 2.Moreover, the forming box is adapted so that it canfollow the web somedistance in the direction of movement of the same during the formingoperation itself, thereafter rapidly to revert to the original positionfor the processing of a nonprocessed part of the web. Instead of aforming box the forming tool may consist of a number of forming bodieswhich are designed for the same purpose as the said forming box, theforming bodies being arranged so that they run on an endless chainunderneath the material web 2. In the case of such an arrangement thecontainers formed in the forming bodies can be allowed to remain in theforming cavity of the forming bodies for an appreciably longer time thanwhat is possible otherwise for a rational forming process. In the courseof this the container bodies can cool down in the forming cavity withoutspecial cooling having to be applied and also better conditions for apre- ,vention of a shrinkage of the material being obtained.Furthermore, in this manner the thermoformable material web 2 is given anecessary push up during the transport through the sterile chamber 4 aswell as a support at the different working operations.

On the side opposite the thermoformable material web 2, that is to sayin the sterile chamber 4, a tool may be arranged for a positive formingeffect on the material web 2. In the sterile chamber 4 there is also afiller 22, which is adapted so that it fills the container bodies 21with sterile goods. Furthermore, a sealing device 23 is provided in thechamber 4, which for example by means of heat and pressure and by meansof compression plates 24 seals the said second web 3 to the material web2, so that the sterile goods filled into the container bodies 21 becomesenclosed. In the upper part of the tunnel 1 is an intake 18 for sterileair, which air is introduced into the sterile chamber 4 and is containedin the same, preferably under a certain pressure.

Before the thermoformable material web 2 is subjected to a thermoformingprocessing by means of the forming tools 19, 20, the material web has tobe heated up to a temperature necessary for the thermoformingprocessing, that is to say to a suitable degree of softening. Thisheeating operation is carried out appropriately outside the sterilechamber 4, because the sterile atmosphere contained in the chamber maybecome mixed with medium evaporating off the web. In FIG. 1 the heatingelements are indicated by reference numeral 12, which are arrangedoutside the sterile chamber 4. These heating elements may consist forexample of heating spirals designed for electric heating. The heatingoperation may be carried out, as shown in the figure, in a chamber,-which in turn may consist of the said pre-treatment chamber. The upperpart'of the pretreatment chamber 5 may be provided with an element 17for extracting by suction the atmosphere contained in the chamber.Furthermore, the pre-treatment chamber may be provided instead or at thesame time with different elements for the washing and/or sterilizationof the material web 2.

The said pre-treatment chambers 5 and 6 are intended foremost to containelements for the cleaning of the two respective material webs 2, 3 bymeans of washing and/or sterilizing before they are introduced into thesterile chamber 4. The element 11 may be adapted so as to irradiate thewebs with ultraviolet light, the element 4 for electron spraying of thewebs or bath and spray devices containing hydrogen peroxide, alcohol orsome other sterilizing, washing or disinfecting fluid which is kept inthe bath or which is applied to the webs in the form f finely dividedparticles. Traces of such liquid medium can be removed from the webs byevaporation, suitable heating elements for the purpose being arranged inchambers 5, 6. By means of these heating elements or by means of thesaid elements 12 provided for the heating of the material web 2 to therequired thermoforming processing temperature, the web can be subjectedto a thermal sterilization. In both the pre-treatment chambers 5 and 6sterile atmospheres are of course being maintained for this purpose andsuitable delimitations exist against the atmosphere surrounding thechambers.

For the introduction of the two material webs 2 and 3 into the steriletunnel 1 or the pre-treatment chambers 5, 6 and for the passing out fromthe sterile tunnel of the combined first and second webs 2 and 3, theelements 15, 15' and 15" are provided at the entrance 13, 13, 36, 36'and at the exit 37 respectively, which prevent the surroundingatmosphere from penetrating into the tunnel 1 and/or the chambers 5 and6. These elements may consist of a sluice comprising a suitblesterilizing or disinfecting fluid, an air curtain consisting of asterile air stream, a liquid curtain consisting of finely dividedparticles of hydrogen peroxide, alcohol or a washing or disinfecting,non-corrosive liquid, a sleeve element or any other means which preventsthe surrounding atmosphere from penetrating into the tunnel and/or thechambers.

The pre-treatment chambers 5 and 6 respectively must be separated fromthe sterile chamber, which can be done in the simplest form by a screenwall 14 and 35 respectively, the pressure of sterile air prevailing inthe Sterile chamber 4 being made to flow out to the pretreatmentchambers through the openings 13 and 36 respectively which are arrangedbetween the screen walls and the material webs 2 and 3 respectively. Thepre-treatment chambers can also be separated from the sterile chamber bymeans of a sluice, a liquid or air curtain or any other suitablearrangement.

The washing and/or sterilization process must be carried out outside thesterile chamber 4. If liquid or gaseous washing and/or sterilizationagents are used, the said processes must likewise be carried out outsidethe pre-treatment chambers 5, 6, since the agents, if used in thepre-treatment chambers, may be blended into the atmosphere contained inthe chambers and there is an obvious danger, in spite of the presence ofsluices or similar arrangements between the pre-treatment chambers andthe sterile chamber, that the atmosphere mixed with washing and/orsterilization agents may penetrate into the sterile chamber 4 or thatsuch agents may precipitate in liquid form (condensation) on thematerial web to accompany the same into the sterile chamber.

As can be seen in FIG. 1, vats 8 and 28 are arranged outside thepretreatment chambers 5 and 6 respectively. These vats are intended tocontain a washing and/or sterilizing liquid 9 and 29 respectively forthe material webs 2 and 3, consisting for example of an alcohol or ahydrogen peroxide solution. Behind the tanks are arranged elements 10and 31 respectively for the absorption of the surplus liquid and heatingelements 16 and 32 respectively in the form of for example heatingspirals for the heating of the respective web so that the residues ofthe treatment fluids evaporate. For the removal of the surplus fluid itis also possible for example to use an air knife, such as that indicatedin FIG. 1 by numeral 30, with the surplus liquid flowing or drippingback into the vat 28.

Outside the exit of the sterile chamber 4 is arranged a knife or shearelement 38, which is intended to separate the filled and sealedcontainers from one another by means of a cut through the two materialwebs 2 and 3. Possible surplus material from the said second materialweb 3 may be rolled up on a roller 39. An endless belt 40 or anothersuitable transport device is arranged for taking over the separatedpacking containers 41.

In FIG. 2aFlG. 2e there is shown a cross-section of the sterile chamber4 in different manners of realization. The figures show, that thesterile chamber consists on the one hand of the said tunnel 1, on theother hand of the thermoformable material web 2 which constitutes thebottom of the sterile chamber. Since the sterile chamber consists of twoparts movable in relation to one another, a seal has to be providedbetween the parts which is satisfactory in respect of the asepticconditions. According to FIG. 2a it is intended that the pressureprevailing in the sterile chamber 4 shall be allowed to seep out in thecracks 42 which have to be maintained between the longitudinal edges ofthe web 2 and the side walls of the tunnel 1.

FIG. 2 b differs from FIG. 2 a only in that the bottom portions of thewall 43 have been folded-in a bit under the thermoformable material web2 so as to form a better protection against the surrounding atmosphere.According to FIG. 2c the longitudinal edges of the thermoformablematerial web 2 are allowed to run in a liquid 45 which is contained in achannel 44 running along each web edge. Each of the channels can beconstructed as a container closed in itself which has, however, alongitudinal opening matched to the web'edges, so that the respectivelongitudinal edge portions of the web can project into an adjacentchannel 44. With the object of achieving a seal the said opening in eachchannel can be provided with sleeves or the like. In the manner ofrealization shown in FIG. 2d, the longitudinal web edges of thethermoformable material web 2 likewise run in a liquid 49. Here too theliquid is contained in elongated channels or containers 48 which arearranged adjoining to the web edges. In this case, however, the edgeportions on the material web have been folded over in such a manner thatfrom the horizontally guided web, edge flanges 46 largely extendingvertically downwards, are obtained. Here the bottom portions of the sidewalls 47 of the tunnel are also allowed to dip into the same liquid, asa result of which a liquid sluice is formed between the walls of thetunnel and the longitudinal edge portions of the thermoformable materialweb. According to FIG. 2e the side walls of the tunnel 1 are allowed toextend to a position just above the longitudinal edge portions of thematerial web 2, so that preferably only the necessary slits 51 betweenthe tunnel walls and the material web are obtained. The web must thenhave a width which at least corresponds to the width of the tunnel, butwhich preferably somewhat exceeds the width of the latter, so that thesterile chamber 4 can be sealed in a satisfactory manner against thesurrounding atmosphere. Reference numeral 50 indicates the element forthe formation of a liquid or preferably air curtain as a screeningagent. Different types of sleeves, or any other element, are alsoconceivable as screening agent in this context.

The thermoformable material web 2 may consist of a polyvinylidenechloride-coated polyvinylchloride web, a polyvinylidene chloride-coatedpolystyrene web, a co-extruded web consisting of apolyethylenepolyvinylidene chloride-polyethylene combination, anacrylonitrile copolymer built up of polystyrenepolyvinylidenechloride-polyethylene. Other combinations may of course also be used inthe building up of a thermoformable material web which can be used inthis connection. Thus two or more of the following materials, namelypolystyrene, polyvinylidene chloride, polyethylene, polyvinylchlorideand also aluminium foil can be combined. The said second material web 3may be built up of a multi-layer material consisting of a metal foil, apolyethylene layer, a more rigid layer consisting of fibres or polyesterand a preoxylene-based coating which is heat-scalable. Other materialcompositions are of course conceivable.

When applying the set-up described, the following procedure is observed.Before the forming and filling process itself is started, the sterilechamber 4 and the pre-treatment chambers 5 and 6, if such are used, mustbe set up, which is done in that at least the thermoformable plasticmaterial web 2 is introduced into the tunnel 1. Subsequently the sterilechamber and the pretreatment chambers 5, 6, if any, have to besterilized and/or disinfected, which implies that the elements situatedin the sterile chamber, such as the forming elements 20, the fillers 22and so on become washed and sterilized.

In the course of the packing, as can be seen from FIG. 1, thethermoformable material web 2 is passed from a roller 7 and down into avat 8 containing a washing and/or sterilizing liquid 9 for the purposeof cleaning or washing and sterilizing the material web 2. After the vat8 the surplus liquid is absorbed or removed in some other manner fromthe web 2 by means of the element 10 designed for this purpose. Usuallythis is followed by a heating of the web by means of the heating element16 shown, so that any residues of the treatment liquids evaporate. Afterthese operations the thermoformable material web 2 would be ready to beintroduced into the sterile chamber. As mentioned earlier, however, theweb has to be heated to the required thermoforming processingtemperature before it is introduced into the sterile chamber. In thiscase the heating elements intended for this are arranged in the vicinityof the inlet opening 13 of the sterile chamber, so that the web isstrongly heated when it is introduced into the chamber, the heatingoperation acting as a disinfecting sluice for the entrance of the webinto the sterile chamber. The said special heating element 16 for thedrying of the web would then probably be omitted.

In accordance with the embodiment shown in the figure, however, thethermoformable material web 2 is introduced into the sterile tunnel 1after cleaning and drying operations. The web is introduced into thesterile tunnel in a preferably horizontal plane and in a substantiallyeven layer. At this entrance into the tunnel the web is passed throughor via a sluice or some other element which is arranged so as to delimitthe sterile chamber against the surrounding atmosphere. If the materialweb is introduced, as mentioned, in an even layer and substantiallyhorizontally, the element delimiting against the environment may consistsimply of a vertically directed curtain consisting of sterile air. Thecurtain will then form an extension of the end wall of the steriletunnel 1.

The front part of the sterile chamber 4 is realized according to FIG. 1as a pre-treatment chamber, where the web 2 can be subjected to asterilizing and/or disinfecting effect by means of different elements oragents. This pretreatment chamber 5 may also be arranged for the heatingof the material web 2 to the necessary thermoforming processingtemperature, the material web 2 being subjected in this same heatingprocess to a thermal sterilization. The material web 2 thus passes afterentrance into the sterile tunnel 1 an element 11 which may be providedfor subjecting the web to electron spraying and/or ultraviolet light forthe purpose of disinfecting and/or sterilizing the web before beingintroduced into the sterile chamber 4. Furthermore, the material web 2,before being introduced into the sterile chamber, passes the heatingelement 12, where the web is heated up to the temperature required forthermoforming processing. If the web is to be formed with folded overedge portions 46 in accordance with the sterile chamber design as shownin FIG. 2d, it will be appropriate to carry out this folding-overoperation in connection with, or after, the said heating operation.

When the material web has a degree of softening suitable for thethermoforming processing, it is introduced into the sterile chamberitself. The sterile chamber 4 is delimited against the pre-treatmentchamber 5 in such a manner that the atmosphere maintained in thepretreatment chamber should not be able to penetrate into the sterilechamber. By keeping the atmosphere maintained in the sterile chamber 4under pressure, the delimitation between the chamber may consist simplyof a single screen wall 14 or the like, as shown in the figure, thematerial web being introduced into the sterile chamber through the inletopening 13.

The material web 2 thus heated to softening is subjected subsequently tothe thermoforming processing by means of the forming elements 19 and/or20 with the object of forming container bodies 21, which in a laterstage are filled with the sterile goods intended for packaging by meansof the fillers 22 shown. After the containers have been filled they mustbe sealed, which is done by applying the said second material web 3 tothe thermoformable material web 2 so that it is wholly covered.

As can be seen from FIG. 1 the said second material web 3 is passed downfrom a roller 27 into a vat 28 which contains a cleaning, washing and/orsterilizing liquid similarly to the set-up for the treatment of thefirst thermoformable material web 2. After the web 3 has passed the vat28, the surplus fluid is drawn off the web by means of the air knife 30shown or by an ab sorbing element 31. Subsequently the web passes aheating element 32, whereby any residual traces of the treatment fluidsare evaporated. The material web 3 is then introduced into thepre-treatment chamber 6 through its opening 36'. In the opening the webpasses the element which is intended to form a sluice or a curtain, sothat the atmosphere surrounding the chamber cannot penetrate into thechamber. If the material web is introduced into the pre-treatmentchamber in a substantially horizontal or vertical position and the webpresents substantially even surfaces, the said element may be designedfor the production of a vertical or horizontal sterile air curtain orair seal, which fills out the interspace between the walls of thechamber and the surface of the material web. In the pretreatment chamber6 the material web 3 passes further various elements 34 for thedisinfection and/or sterilization of the web, whereby it is possible, asmentioned earlier, for the elements to be arranged so as to subject theweb to electron spraying and/or ultraviolet light. Subsequently, thematerial web 3 is introduced into the sterile chamber 4 to be joined tothe first thermoformable material web 2. The web 3 passes through anopening 36 in the wall of the sterile tunnel 1. This pretreatmentchamber 6, similar to the other pretreatment chamber 5, is separatedfrom the sterile chambeer 4 by means of a screen wall 35 or the like.

The said second material web 3 is applied and sealed to, or joined insome other manner to, the first thermoformable material web, and this isdone at least along zones closed in themselves around the openings onthe container bodies 21 formed in the material web, so that the sterilegoods filled into the containers are enclosed. The sealing or closuresare done for example by means of heat and pressure with the tool 23shown in the fig ure. The material web 3 applied is fitted so that itpreferably wholly covers the thermoformable material web 2 and forms asubstantially even upper side on this web. The container bodies 21 sosealed are then passed out of the sterile tunnel 1 Whilst they continueto be attached to one another, and form a substantially even surfacetowards the tunnel or the chamber.

On leaving the sterile tunnel 1, the combined first and second materialwebs 2, 3 pass a curtain 15, a sluice or some other element whichscreens the opening or mouth 37 of the tunnel in such a manner, that theatmosphere existing outside the sterile chamber 4 cannot penetratethrough the said opening. Since the thermoformable material web 2 hasbeen given an even upper side through the application of the secondmaterial web 3 and in this case the combined first and second materialwebs 2, 3 are passed substantially horizontally out of the tunnel l, thesaid curtain or sluice element 15' may consist of a device for thegeneration of a laminar, vertically directed sterile air stream which inthe form of a curtain fills the space between the end wall of the tunnell and the upper side of the combined webs.

After the formed, filled and sealed containers 2i have been passed outfrom the tunnel 1, they are separated from one another by means ofknives or som other suitable element 38 in that the two said webs 2., 3are cut through or severed between the container bodies formed, so thatseparate container units 41 are obtained. Any surplus of the said secondand covering material web 3 can be rolled up on a roller 39. Theseparated containers 41 are removed lastly on a conveyor 40 for furthertreatment, for example for packing in transport containers, or the like.

Without exceeding the scope of the concept of the invention,modifications may be made to the process described. Thus it is quitepossible to introduce into the sterile chamber 4 a gas activelysterilizing in itself instead of the said sterilizing air with theobject of sterilizing or disinfecting the chamber and to maintain asterile atmosphere in the ,same. In the packaging processes forfoodstuffs sterilizing air is to be preferred, however.

Furthermore, the openings 13 and 36 between the sterile chamber 4 andthe pre-treatment chambers 5 and 6 respectively, if any, may havespecial elements for the delimiting of the chambers from one another.Such elements may consist of a liquid seal filled with a suitableliquid, an air curtain consisting of a laminar, sterile air stream, aliquid curtain consisting of for example finely divided hydrogenperoxide or alcohol particles a sleeve element or some other means forpreventing the atmosphere prevailing in the pre-treatment chambers frompenetrating into the sterile chamber 4. The elements or agents mentionedhere are specially applicable for the purpose of screening the sterilechamber 4 and the pre-treatment chambers 5, 6 in the limit zones of thesame towards, or the inlet and outlet openings to, the atmospheresurrounding the chambers.

The said pre-treatment chambers 5, 6 may of course take the mostsuitable shape and they may thus be quite different from the designreferred to in the description and shown in the figures. Thus they neednot, as is the case in the pretreatment chamber 5 shown in FIG. 1,consist of partly a tunnel, partly a material web which in fact isintended for further processing to container bodies. It would also bepossible, if this were found appropriate, and as pointed out earlier,wholly to eliminate the pre-treatment chambers 5, 6. The heating element12 provided outside the sterile chamber 4 for the heating of thethermoformable material web 2 constitutes an advantageous treatment sothat the material web should be able to be introduced directly into thesterile chamber. It is also conceivable, however, to allow the secondmaterial web 3 to pass a heated zone before or during its introductioninto the sterile chamber 4, which means that in certain cases thepretreatment chamber 6 could be discarded.

The material or combination of materials in the first and secondmaterial webs 2, 3 applied can of course be different from the onessuggested earlier. As a sole example may be mentioned that the saidsecond and closing material web 3 may consist of simply a metal foil,for example an aluminium foil, which is coated possibly with for examplea thermally active, adhesion promoting agent.

It must be emphasized, that it is essential, that the thermoformablematerial web 2, the said second material web 3 and/or the combinedmaterial webs 2, 3 are passed into and out of the sterile unit as limitsto the surrounding atmosphere with a surface or upper side which iseven, and that the web or webs are conveyed in an either substantiallyhorizontal plane or vertical plane. Furthermore, it is essential thatthe said first material web 2 and/or the combined first and secondmaterial webs 2, 3 together with the sterile tunnel 1 form the saidsterile chamber 4, that is to say that the material web and the combinedwebs 2, 3 constitute a side wall in the sterile chamber.

The configuration of the set-up shown in the figures on the outside ofthe said chambers 4, 5 and 6 is thus of less importance. For the sake ofcompleteness it should be mentioned however, that the material webs 2and 3 each by itself and in combined form are supported, guided etc. bymeans of guide rails, rolls or other suitable elements which in asatisfactory manner can bring the webs or the combined webs in the rightposition or positions during the various courses from the rolling offfrom the respective supply rollers 7, 27 and until the filled, sealedand separated containers 41 have been obtained. The invention is notlimited therefore to the embodiment shown, but only by the follow-- ingpatent claims.

I claim:

1. A method for forming, filling and sealing containers under asepticconditions from a first web of substantially impermeable thermoformablematerial of indeterminate length comprising moving the first web in thedirection of its length with one surface facing a sterile chamber andcooperating therewith to constitute one outer wall thereof by forming asubstantial seal therewith, forming a plurality of container elements inthe first web, introducing a filler material into the containerelements, applying a second web of substantially impermeablethermoformable material to the filled container elements, and sealingthe second web to the first web to close and seal the filled containerelements, the steps of forming the container elements, filling thecontainer elements and applying and sealing the second web to the filledcontainer elements being carried out while the first web constitutes theone outer wall of the sterile chamber and finally separating the filledand sealed containers after leaving the sterile chamber.

2. A method as claimed in claim 1 wherein the first web is sterilizedbefore it forms the one wall of the sterile chamber.

3. A method as claimed in claim 1 wherein a sterile gas is passed intosaid sterile chamber under a pressure exceeding that of the surroundingair so as to prevent surrounding air from entering said sterile chamber.

1. A method for forming, filling and sealing containers under asepticconditions from a first web of substantially impermeable thermoformablematerial of indeterminate length comprising moving the first web in thedirection of its length with one surface facing a sterile chamber andcooperating therewith to constitute one outer wall thereof by forming asubstantial seal therewith, forming a plurality of container elements inthe first web, introducing a filler material into the containerelements, applying a second web of substantially impermeablethermoformable material to the filled container elements, and sealingthe second web to the first web to close and seal the filled containerelements, the steps of forming the container elements, filling thecontainer elements and applying and sealing the second web to the filledcontainer elements being carried out while the first web constitutes theone outer wall of the sterile chamber and finally separating the filledand sealed containers after leaving the sterile chamber.
 2. A method asclaimed in claim 1 wherein the first web is sterilized before it formsthe one wall of the sterile chamber.
 3. A method as claimed in claim 1wherein a sterile gas is passed into said sterile chamber under apressure exceeding that of the surrounding air so as to preventsurrounding air from entering said sterile chamber.